Human immunodeficiency virus type 1: drug resistance in treated and untreated Brazilian children

Twenty-two vertically human immunodeficiency virus type 1 (HIV-1) infected Brazilian children were studied for antiretroviral drug resistance. They were separated into 2 groups according to the administration of antiretroviral therapy into those who presented disease symptoms or without symptoms and no therapy. Viral genome sequencing reactions were loaded on an automated DNA sampler (TruGene, Visible Genetics) and compared to a database of wild type HIV-1. In the former group 8 of 12 children presented isolates with mutations conferring resistance to protease inhibitors (PIs), 7 presented isolates resistant to nucleoside reverse transcriptase inhibitors (NRTIs) and 2 presented isolates resistant to non-nucleoside reverse transcriptase inhibitors (NNRTIs). Ten children were included in the antiretroviral naﶥ group. Eight were susceptible to NRTIs and all of them were susceptible to PIs; one presented the V108I mutation, which confers low-level resistance to NNRTIs. The data report HIV mutant isolates both in treated and untreated infants. However, the frequency and the level of drug resistance were more frequent in the group receiving antiretroviral therapy, corroborating the concept of selective pressure acting on the emergence of resistant viral strains. The children who presented alterations at polymorphism sites should be monitored for the development of additional mutations occurring at relevant resistance codons

Virus da Imunodeficiencia Humana: considerações gerais sobre a especificidade e sensibilidade de metodos laboratoriais para a detecção de anticorpos e antigenos especificos / Human immunodeficiency virus: general aspects concerning laboratorial methods specificity and sensitivity to detect specific antigens and antibodies

O diagnostico laboratorial da infeccao pelo virus da imunodeficiencia humana tipo 1 pode ser feito mediante a aplicacao de testes sorologicos de terceira geracao. Reatividade inespecificas podem, entretanto, ser observadas em diferentess grupos populacionais, para a deteccao de anticorpos contra HIV por metodos imunoenzimaticos, conforme observado na analise de amostras sorologicas de gestantes (3,9 porcento), hepatopatas (3,0 porcento) e populacao pediatrica (1,03 porcento). Os valores de inespecificidade reforcam o conceito de que a deteccao de anticorpos contra HIV deve ser feita pela analise e interpretacao de, ao menos, dois testes de diferentes procedencias, em uma primeira coleta. Metodos de triagem de quarta geracao, que permitem a deteccao simultanea de anticorpos e antigeno p24 do HIV, apresentam sensibilidade comparavel a das metodologias tradicionais, sendo de particular valor no diagnostico precoce da infeccao. Diferentes amostras de sangue de tres pacientes, coletadas em periodos distintos, foram analisadas comparativamente por testes imunoenzimaticos de terceira geracao (Cobas, Axsym e Ortho) e quarta geracao (ELFA HIV DUO). Os resultados demonstram a possibilidade de antecipar a deteccao dos marcadores da infeccao viral em periodos que podem variar de quatro a 12 dias, quando comparados a metodos de terceira geracao, que detectam apenas anticorpos

Detection of hepatitis B virus antigens in paraffin-embedded liver specimens from the Amazon Region, Brazil

Hepatic viscerotomy of paraffin-preserved old specimens, collected in the period from 1934 to 1967, were analyzed by immunohistochemical assays to detect hepatitis B, hepatitis D, dengue and yellow fever virus antigens. The material belongs to the Yellow Fever Collection, Department of Pathology, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil and the cases were diagnosed at that time according to clinical aspects and histopathological findings reporting viral hepatitis, yellow fever, focal necrosis and hepatic atrophy. From the 79 specimens, 69 were collected at the Labrea Region and the other 10 in different other localities in the Amazon Region. The five micra thick histological slices were analyzed for the presence of hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) by immunoperoxidase technique. An immunofluorescence assay was applied to the detection of hepatitis D, yellow fever and dengue virus antigens. Nine (11.4 percent) histological samples were HBsAg reactive and 5 (6.3 percent) were HBcAg reactive. The oldest reactive sample was from 1934. Viral antigens related to the other pathologies were not detected in this study. Our results confirm that the methodology described may be used to elucidate the aetiology of hepatitis diseases even after a long time of conservation of the specimens